EPA-600/3-76-005
JANUARY 1976
Ecological Research Series
AMERICIUM - ITS BEHAVIOR IN SOIL AND
PLANT SYSTEMS
Environmental Monitoring and Support Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Las Vegas, Nevada 89114
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into five series. These five broad
categories were established to facilitate further development and application of
environmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The five series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socio-economic Environmental Studies
This report has been assigned to the ECOLOGICAL RESEARCH series. This series
describes research on the effects of pollution on humans, plant and animal
species, and materials. Problems are assessed for their long- and short-term
influences. Investigations include formation, transport, and pathway studies to
determine the fate of pollutants and their effects. This work provides the technical
basis for setting standards to minimize undesirable changes in living organisms
in the aquatic, terrestrial, and atmospheric environments.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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EPA-600/3-76-005
January 1976
AMERICIUM - ITS BEHAVIOR IN SOIL AND PLANT SYSTEMS
by
K. W. Brown
Monitoring Systems Research and Development Division
Environmental Monitoring and Support Laboratory
Las Vegas, Nevada 89114
ROAP No. 21AMI
Program Element No. 1FA083
U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF RESEARCH AND DEVELOPMENT
ENVIRONMENTAL MONITORING AND SUPPORT LABORATORY
LAS VEGAS, NEVADA 89114
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DISCLAIMER
This report has been reviewed by the Environmental Monitoring and Support
Laboratory, U.S. Environmental Protection Agency, and approved for publication.
Mention of trade names or commercial products does not constitute endorsement
or recommendation for use.
ii
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CONTENTS
Page
ACKNOWLEDGMENT iv
INTRODUCTION 1
AMERICIUM IN THE SOIL SYSTEM 2
AMERICIUM IN THE PLANT SYSTEM 3
SUMMARY 6
LITERATURE CITED 8
iii
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ACKNOWLEDGMENT
The assistance of R. 0. Houston in obtaining the reported data for the
completion of this project is gratefully acknowledged.
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INTRODUCTION
The release of long-lived radioactive elements into the biosphere in past
years by atmospheric nuclear testing and currently by the expanding nuclear
power industry has prompted the need for assessing the impact of these pol-
lutants on our environment. Studies of various radionuclides by Hanson and
Eberhardt (1971), Romney et al. (1971), Williams (1967), and Koranda et al.
(1969), have shown that once released, many radioactive pollutants tend to
accumulate in the environment ,in different forms and also in one of the many
trophic levels of a biological system. Although little is known about the be-
havior and transfer kinetics of many radioactive pollutants in the soil and
plant environment, the foregoing studies have shown that their movements in
both the edaphic and biotic compartments were found to be, in general, very
slow. As reported by Price (1973a), the final assessment of environmental
impact will show that pollutants having long residence times will increase in
relative importance with time, especially in areas where they are uncontained
within the biosphere.
Some of the longest lived and abundant radioactive pollutants being re-
leased into our environment are the transuranic elements. For example, Jacobs
and Gera (1969) have projected that the accumulation of plutonium and its decay
products from the United States nuclear power industry will exceed 1,000 meg-
acuries by the year 2020. Another investigator (McKay 1961) reported that the
most biologically hazardous radioelements being produced by our nuclear indus-
try in addition to plutonium are other actinides, americium, neptunium and
curium. This was substantiated by Denham (1969) when he reported on the
radiological hazards of the transuranic elements.
Three excellent review articles have been published on the chemical and
physical behavior of the transuranic elements in biotic systems. Two of these
authored by Price (1973a) and Francis (1973) are primarily concerned with ter-
restrial behavior. The other, authored by Noshkin (1972), is concerned with
the behavior,and dissemination of these radioactive pollutants in aquatic envi-
ronments .
It is evident from the scientific literature that most biological inves-
tigations conducted concerning the transuranic elements were focused primarily
on plutonium, which is considered to be the most dangerous to man. For the
most part, the other transuranic elements were studied in an ancillary manner,
and consequently, relatively few reports exist concerning their fate and be-
havior in the environment.
During the past few years, the scientific community has become increas-
ingly aware of americium as being a major radioactive pollutant. Of its twelve
isotopes, americium-241 :is generally considered to present the most serious en-
vironmental hazard. Americium-241 enters .the environment primarily as a decay
product of plutonium-241i which is released into our biosphere as a by-product
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of both the nuclear testing program and the nuclear power industry. Americium-
241, like its parent, is a long-lived radionuclide that will accumulate in our
environment and may become more biologically available with time. Poet and
Martell (1972) estimated that the maximum environmental impact of americium-241
following an accidental release of plutonium-241 would probably occur in 70 to
80 years. Also, Major et al. (1974) suggested that high priority be given to
investigations involving americium, as nearly 26 years have passed since the
initial release of plutonium-241 into our environment. This review was under-
taken to assemble and summarize the available data concerning the distribution
and behavior of americium in both soil and plant systems and also to identify
areas of needed investigation.
AMERICIUM IN THE SOIL SYSTEM
The main research goals of many investigations have been to determine the
pathways and rates of radionuclide transfer among the many components of both
native and agricultural ecosystems. Studies of soil, soil-plant, and plant
systems can serve to show mechanisms by which americium could become incorpo-
rated into biological systems. Many studies have been initiated following
accidental or continual releases of radioactive pollutants into our environ-
ment, while others have been conducted under controlled conditions using
radioisotopes as tracers. Both types of investigations have added to our un-
derstanding and knowledge of the complexity of these pollutants in our envi-
ronment.
Many studies involving transuranic elements in soils have been conducted
on or near the U.S. Energy Research and Development Administration's (formerly
the U.S. Atomic Energy Commission) Nevada Test Site following nuclear testing.
Experimentation has also been conducted in areas used for the disposal of both
liquid and solid radioactive wastes. These studies were initiated due to past
practices of using soils to sorb and retain radionuclides.
Some of the earliest work conducted concerning actinide behavior in soils
was accomplished by Rhoads (1957). He reported various characteristics of
Plutonium adsorption by soil collected near the Hanford Disposal Site. Approx-
imately 10 years later, Hajek (1966), using soils collected from the radioac-
tive waste cribs near Richland, Washington, reported on the mobility of ameri-
cium in soil. After leaching aliquots of soil containing americium and plu-
tonium with both water and a solution of Iff NaN03, Hajek found that 7.5% of the
americium was removed from the soil with the water treatments while 33% was
leached with the NaN03. A similar study using gravity-fed soil columns to
investigate the ionic exchange properties of americium-241 was conducted by
Knoll (1969). After applying various organic compounds tagged with americium-
241 to soil columns, he reported that the soil had little or no effect on
removing the americium from any of the compounds tested. However, americium
previously applied to soil was rapidly and completely leached by both
di-(2-ethylhexyl) phosphoric and hydroxyacetic acids.
A study by Wallace (1972a) showed that the common chelating agent di-
ethylenetriaminepentaacetic acid (DTPA) can be used to increase the uptake of
americium-241 by plants and that it was also an excellent soil extractant for
americium-241. Cline (1968) revealed that soil pH affects the downward
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migration rate of americium-241. He applied 2ttlAm(N03)i+ to two different
soils, one having a pH of 4.5 and the other 7.5. His results showed that,
after each column was leached with 100 inches of irrigation water, in excess of
981 of the americium was retained in the top 1 centimeter of the acid soil,
whereas only 76% remained in the top layer of the basic soil. Maximum depth of
penetration was noted when americium was detected near 20 centimeters in the
basic soil and only at the 5-centimeter depth in the acidic soil.
The foregoing studies concentrated on the extraction or leaching of amer-
icium from soil with a variety of solvents or solutions. From these findings,
it is evident that americium interacts both chemically and physically with
various types of soil. However, it should be noted that these studies were
limited in scope and definitive deductions cannot be derived from the resulting
data. This is primiarily due to the physical and chemical complexity of soils
and their effects on the various chemical forms of americium, which apparently
have not been extensively investigated relative to americium behavior.
The application and use of americium as a tracer in soil studies, such as
in the determinations of both soil density and soil water content, have in-
creased in recent years. King (1968) reported that the use of americium for
these determinations was not fully investigated until after 1962 due to its
limited availability, Since then, King (1968), DeSwart and Groenevelt (1971),
Corey et al. (1971), Bridge and Collis-George (1973), and Reginato (1974) have
all shown that americium-241 is a suitable gamma emitter for these determina-
tions. Basically, the method involves measuring the attenuation of collimated
beams of monoenergetic gamma rays passing through soil containing varying
amounts of water. The two advantages of using americium-241 in preference to
other tested gamma-emitting radionuclides for these measurements are: 1) it
has a long half-life of 458 years, and 2) it has a relatively low-energy gamma
ray, having a major peak at 60 keV, therefore requiring less shielding for
operator safety.
The transfer, mobility, and biological availability of americium in soils
may be enhanced by soil microorganisms. For example, Au (1974) indicated that
plutonium was assimilated and taken up by Aspevg-illus sp. from a plutonium-
contaminated malt agar. His work suggests that acid-producing soil molds may
solubilize other actinides for assimilation and uptake by soil microorganisms
and higher plants. Unfortunately, there does not appear to be any conclusive
data in the literature concerning microbial effects on americium. However,
studies are underway to determine the role of selected soil microorganisms in
the complexing of various soil constitutents in soils contaminated with pluton-
ium or americium.
AMERICIUM IN THE PLANT SYSTEM
Rediske et al. (1955) indicated that the majority of the radioactive
nuclides incorporated into biological systems entered via plants. One means of
incorporation is by the interception and retention of airborne contaminants by
aerial portions of plants with subsequent transport between the different
trophic levels. Another method is the deposition of contaminants on soils with
eventual root absorption.
As with soil investigations, relatively few plant studies have been
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conducted to determine the magnitude of root absorption using both contaminated
soil and hydroponic rooting media. The data from these investigations indicate
that the amount of americium absorption is similar to-that of many heavy metals
(Price, 1973a). Apparently, the only studies concerning biological incorpor-
ation of alpha-emitting nuclides by foliar deposition are being conducted at
the U.S. Energy Research and Development Administration's Nevada Test Site. In
these studies, Earth (1974) and Smith (1974) showed that the concentration of
alpha-emitting nuclides increased in cattle rumen ingesta following the inges-
tion of Ewfotia lanata. Their conclusion was that this increased concentration
was due primarily to the relatively high deposition and physical retention of
particles by this species. While studying plant uptake and.the retention of
selected actinides, Romney et al. (1974) also found this plant species to be an
excellent collector of airborne contamination.
Foliar uptake and retention following the immersion of orange leaves in
various solutions containing americium-241 were studied by Wallace et al.
(1969). They found that the absorption of americium-241 increased with an
increase in solution pH. However, when the chelating agent DTPA was added to
the solutions, a decrease in americium-241 absorption occurred. The maximum
absorption of americium with DTPA occurred at a solution pH of 2.0, decreased
at a pH of 5.0, and leveled off at a pH of 8.0. They concluded that at a pH of
2.0 the DTPA had no effect presumably because the compTexing of americium-241
cannot take place under highly acidic conditions.
The uptake of radioisotopes via the roots of plants generally results in a
long-term radionuclide plant burden. For example, Romney et al. (1970) found
that during a 5-year cropping study, a consistent yearly increase in plant
tissue concentration occurred. They concluded that the increase in uptake was
due either to an ever-expanding root system, which would physically increase
the probability of the roots coming in contact with the radionuclide, or that a
chemical transformation occurred as a result of an increase in soil organic
matter from root tissue decay.
Several different chemicals were added to soils containing americium to
determine their effects on plant uptake. This study by Hale and Wallace (1970)
showed that a substantial increase in the amount of americium occurred in the
aerial portion of bean plants grown in soils spiked with 10 microcuries of
americium-241 (in HN03) following applications of two different chelating
agents. The chelating agents DTPA and ethylenediamine di(o-hydroxyphenylacetate)
(EDDHA), which were applied at a rate equivalent to 10 pounds of iron per acre,
increased the root uptake of americium by nearly 1,000 and 500 times, respec-
tively.
In similar experiments, Wallace (1972a, 1972b) grew soybeans and citrus
plants in soils spiked with americium. His data showed that the incorporation
of americium-241 in both species increased with applications of DTPA. The
translocation and percentage composition of absorbed americium-241 in bush
beans grown in a nutrient solution spiked with americium-241 was also investi-
gated. His data showed that the majority of the americium was located in the
leaves (62%), followed by the roots (25%), and the stems (13%). The data from
a study to determine the influence of soil pH on the chelation of americium-241
by DTPA were also reported by Wallace. The data showed that the greatest
uptake of americium by bush beans occurred in soils with a pH of 7.7. Also the
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ratio of americium-241 in the leaf versus that in the stems was greatest at
this pH.
The uptake of americium by beans grown in a standard Hoaglands solution
(Hoagland and Arnon 1950) containing 0.9 pCi/liter of 2tflAm(N03)3 and barley
grown in two different soils spiked with 1.8 yCi/g of 2'tlArn(N03)1+ was investi-
gated by Cline (1968). He reported that the ratio of americium in the leaves
to that in the rooting media, soil or solution, was nearly identical for each
species. The pH of the soils used by Cline, one having a pH of 4.5, the other
7.5, did not appear to influence the uptake of americium. This is interesting
as Wallace (1972a) reported that soil pH without the addition of chelating
agents did affect the uptake of americium. His data showed that a greater
amount of americium-241 was taken up by plants grown in soils at a pH of 5.3
than those grown in soils with a pH of 8.7.
Evidence of the toxicity of americium to plants was also reported by Cline
(1968). He found that secondary roots were not formed by pea plants grown in a
nutrient solution containing americium at a concentration of 0.1 microcurie per
liter. After an identical treatment using plutonium-239, he concluded that
Plutonium was not as toxic to plants as americium and also that americium-241
could not be used as a reliable tracer for plutonium-239 due to a difference in
uptake which was 20 to 30 times greater for americium than for plutonium.
Cline stated further that studies using plutonium should fully characterize any
accompanying americium contamination before valid conclusions can be drawn.
Price (1972) conducted one of the few studies relevant to radioactive
waste management involving americium. He selected Russian thistle (Salsola
'kali] and cheatgrass (Bramus tectomon) for investigation because of their
abundance and because they are both prolific invaders of disturbed areas. The
seeds of both species were germinated under controlled environmental conditions
in local soil having a pH of 7.8 and spiked with 2ttlAm(N03)3. His data showed
that the uptake and accumulation of atnericium by the Russian thistle was over
twice the amount taken up by the cheatgrass. The magnitude of uptake based on
the amount of americium in the rooting media was 0.032% for the Russian thistle
and 0.0071% for the cheatgrass. The reason for this large difference is
unknown. However, it does indicate that a degree of uncertainty exists in
respect to the uptake of americium by different plant species. This difference
in plant species uptake was again shown by Price (1973b and 1973c). He spiked
the following organic acids, acetate as NH^H^, glycolate as NaC2H303,
oxalate as (NHit)2C2Oit, and citrate as (NHtt)2HC5H507 with approximately 2.5
yCi/ml of 21tlAm. Following the addition of 10 ml of each of these solutions to
local soils, the seeds of Russian thistle and cheatgrass were planted and grown
for approximately 2 months.
After sample analysis, he reported that a 10-fold difference frequently
occurred between the amount of americium taken up by each of these species.
The minimum amount of americium uptake in both species occurred in the glyco-
late treatment with a relative percentage uptake of 8% in the cheatgrass and
64% in the Russian thistle. The maximum uptake of americium by the Russian
thistle was observed during the oxalate treatment with a relative percentage of
79%; whereas a high of 26% occurred in the cheatgrass following the acetate
treatment. Also, his data showed that the apparent complexing of these organic
acids in the soil resulted in a decrease in uptake when compared to his pre-
vious experiment using 241Am(N03)3.
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Another area in need of scientific investigation includes the identifi-
cation and description of the fate and behavior of americium in both fresh
water and marine ecosystems. Our knowledge of this contaminant and its distri-
bution in these environments is limited. This is unfortunate in view of the
many sources of aquatic contamination. Aside from the contribution of atmos-
pheric deposition and wastes from reprocessing facilities (Templeton and
Preston 1966), there have been more than 50 underwater and water surface
nuclear tests conducted on and in the vicinity of the Eniwetok and Bikini
atolls. It is perhaps easily assumed that radionuclides may be far more mobile
in aquatic systems than they are in terrestrial systems. As a result, the rate
of biotic incorporation of radionuclides in aquatic environments is probably
enhanced. The rates and magnitude of americium incorporation into the aquatic
flora is, unfortunately, unknown; however, Noshkin (1972) reported that studies
are presently being conducted by several laboratories to document the concen-
trations and distributions of actinides in major bodies of water.
It appears that some marine plants could possibly be used as environmental
indicators of selected actinides. For example, the free-floating marine algae,
Sargassim sp.f has been reported to have a high affinity for plutonium-239.
This plant has also been reported by Burkholder (1963) and Simek et al. (1967),
to effectively concentrate other radionuclides such as cesium-137, cerium-144,
praseodymium-144 and manganese-59. Recently, Gushing and Watson (1974) re-
ported that americium-241 was found to be incorporated into the tissues of
algae, and other aquatic species including several species of pond weed,
Potamogeton spp.3 following a radiological survey of a low-level radioactive
waste pond.
SUMMARY
The relatively small amount of knowledge that has been gained concerning
the behavior of americium in the soil-plant systems should be, at best, used
conservatively in evaluating the impact of this element in our environment.
Previous investigations have made it apparent that changes in pH and the addi-
tion of various concentrations of complexing or chelating agents to soils will
influence the biological availability of this element in these systems.
It is easily concluded that the chelation of this radionuclide may in-
crease plant uptake and thus lead to man via his food chain. This is a good
possibility not only because of naturally occurring complexing agents, but also
because of the use of commercially available chelating agents in agricultural
areas to enhance the uptake and use-of micronutrients by crop plants. There-
fore, mechanisms of chelation should be explored.
Evidence in the literature indicates that americium can be toxic to
plants and can retard normal plant growth. These effects should be explored.
Also, the factors affecting the biological availability and the mobility of
americium in soil systems, such as by local soil properties and microbial
metabolism, need further investigation. Additionally, the need to identify the
mode, rate, chemical form, and amount of americium incorporated in various
plant organs is evident.
It is generally agreed that americium may become a greater environmental
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liability than the most investigated transuranic element, plutonium. As a
result, a complete documentation of its distribution, fate, and behavior in
our environment is essential, especially in view of our expanding nuclear
industry.
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LITERATURE CITED
Au, F. H. F. (1974), "The role of soil microorganisms in the movement of
Plutonium." The Dynamics of Plutonium in Desert Environments. Nevada Applied
Ecology Group Progress Report. NVO-142, pp. 135-141.
Barth, J. (1974), "The solubility from rumen contents of cattle grazing on
plutonium contaminated desert vegetation in in vitro bovine gastrointestinal
fluids." Presented at the Nevada Applied Ecology Group Annual Conference.
Proceedings in press.
Bridge, B. J. and N. Collis-George (1973), "A dual source gamma ray traversing
mechanism suitable for the non-destructive simultaneous measurement of bulk
density and water content in columns of swelling soil."
Aust. J. Soil Res., 11: pp. 83-92.
Burkholder, P. R. (1963), "Radioactivity in some aquatic plants."
Nature^ 198: pp. 601-603.
Cline, J. F. (1968), "Uptake of 2tflAm and 239Pu by plants." USAEC Report
BNWL-714, Pacific Northwest Laboratory, Richland, Washington, pp. 8,24-8.25.
Corey, J. C., S. F. Peterson, and M. A. Wakat (1971), "Measurement of attenu-
ation of 137Cs and 2ltlAm gamma rays for soil density and water content
determinations." Soil Soi. Soo. Amer. Proo.3 35: pp. 215-219.
Cushing, C. E. and D. G. Watson (1974), "Aquatic studies at Gable Pond."
Pacific Northwest Laboratory Annual Report for 1973 to the USAEC Division
of Biomedical and Environmental Research. Part 2, Ecological Sciences.
BNWL-1850 PT2 UC-48, Battelle Pacific Northwest Laboratories, Richland,
Washington, pp. 96-97.
DeSwart, J. G. and P. H. Groenevelt (1971), "Column scanning with 60 keV
gamma radiation." Soil Soi.3 112: (6), pp. 419-424.
Denham, D. H. (1969), "Health Physics considerations in processing transplu-
tonium elements." Health Phys.3 16: pp. 475-487.
Francis, C. W. (1973), "Plutonium mobility in soil and uptake in plants:
a review." J. Environ. Quality., 2: (1), pp. 67-70.
Hajek, B. F. (1966), "Plutonium and americium mobility in soils." USAEC
Report BNWL-CC-925. Pacific Northwest Laboratory, Richland, Washington,
pp. 1-9.
Hale, V. Q. and A. Wallace (1970), "Effect of chelates on uptake of some
heavy metal radionuclides from soil by bush beans." Soil Soi.j 109: (4),
pp. 262-263.
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Hanson, W. C. and L. L. Eberhardt (1971), "Cycling and compartmentalizing of
radionuclides in northern Alaskan lichen communities." Proceedings, Third
National Symposium on Radioecology, May 10-12, 1971, Oak Ridge, Tennessee.
CONF-710501. pp. 71-75.
Hoagland, D. R. and D. I. Arnon (1950), "The water-culture method for growing
plants without soils." California Agr. Expt. Sta. Cir. 347.
Jacobs, D. 6. and Ferruccio Gera (1969), "Development of criteria for
long-term management of high-level radioactive wastes." Health Physics
Division, Annual Progress Report, Oak Ridge National Lab., Oak Ridge,
Tennessee. ORNL-4446, pp. 1-40..
King, L. G. (1968), "Gamma ray attenuation for soil water content meas-
urements using 2U1Am." Pacific Northwest Laboratory Annual Report for
1967. BNWL-715, Part 4, pp. 17-22.
Knoll, K. C. (1969), "Reactions of organic wastes and soils." Water and
Waste Management Department, Battelle Memorial Institute, Pacific North-
west Laboratory, Richland, Washington. BNWL-860, pp. 1-13.
Koranda, J. J., J. R. Martin, R. W. Wikkerink, and M. Stuart (1969),
Radioecological Studies of Amohitka Island, Aleutian Islands* Alaska.
II. Gamma-emitting Radionuolides in the Terrestrial Environment.
Lawrence Radiation Laboratory, University of California, Livermore.
UCRL-50786, pp. 1-44.
Major, W. J., K. D. Lee, R. A. Wessman, and C. H. Heitz (1974), "A rapid
method for-radiochemical analysis of americium-241." Environmental Anal-
ysis Laboratories, Richmond, California. T.L.W. 6116, pp. 1-8.
McKay, H. A. C. (1961), "Alpha emitters in reactor wastes." Atomic
Energy Waste: Its Nature, Use and Disposal. Interscience, New York,
New York, pp. 99-108.
Noshkin, V. E. (1972), "Ecological aspects of plutonium dissemination
in aquatic environments." Health Phys., 22: pp. 537-549.
Poet, S. E. and E. A. Martell (1972) "Plutonium-239 and americium-241
contamination in the Denver area." Health Phys., 23: pp. 537-548.
Price, K. R. (1972), "Uptake of 237Np, 239Pu, 21tlAm and 21"*Cm. From
soil by tumbleweed and cheatgrass." Battelle, Pacific Northwest Labo-
ratories, Richland, Washington. BNWL-1688, pp. 1-14.
Price, K. R. (1973a), "A review of transuranic elements in soils, plants, and
animals." J. Environ. Quality, 2: (1), pp 62-66.
Price, K. R. (1973b), "The behavior of waste radionuclides in soil-plant
systems." Battelle Pacific Northwest Laboratories, Richland, Washington.
BNWL-1750, pp. 2.4-2.7.
Price, K. R. (1973c), "Tumbleweed and cheatgrass uptake of transuranium
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elements applied to soil as organic acid complexes." Battelle Pacific North-
west Laboratories, Richland, Washington. BNWL-1755, pp. 1-10.
Rediske, J. H., J. F. Cline, and A. A. Selders (1955), "The Absorption of
fission products by plants." USAEC Report HW-36734, pp. 1-17.
Reginato, R. J. (1974), "Gamma radiation measurements of bulk density changes
in a soil pedon following irrigation." Soil Sci. Soc. Amev. Proc., 38:
pp. 24-29.
Rhoads, D. W. (1957), "Adsorption of plutonium by soil." Soil Sci., 84:
pp.465-471.
Romney, E. M., H. M. Mork, and K. H. Larson (1970), "Persistence of Plutonium
in soil, plants, and small mammals." Health Phys., 19: pp. 487-491.
Romney, E. M., W. A. Rhoades, A. Wallace, R. A. Wood (1971), "Persistence of
radionuclides in soil, plants, and small mammals in areas contaminated with
radioactive fallout." Proceedings, Third National Symposium on Radioecology.
May 10-12, 1971, Oak Ridge, Tennessee. CONF-710501, pp. 170-176.
Romney, E. M., A. Wallace, R. 0. Gilbert, S. A. Bamberg, J. D. Childress, J. E.
Kinnear, and T. W. Ackerman (1974), "Some ecological attributes and plutonium
contents of perennial vegetation in Area 13 (NAEG Vegetation Studies)," The
Dynamics of Plutonium in the Desert Environments, Nevada Applied Ecology Group
Progress Report, NV0142, pp. 91106.
Simek, J. E., J. A. Davis and C. E. Day III (1967), "Sorption of radioactive
nuclides by sargassum fluitans and s. nutons." Proceedings of the Second
National Symposium on Radioecology, May 15-17, CONF-670503, pp. 505-508.
Smith, D. D. (1974), "Grazing studies on selected piutorn'urn-contaminated areas
in Nevada." Presented, Nevada Applied Ecology Group Annual Conference.
Proceedings in press.
Templeton, W. L. and A. Preston (1966), "IAEA Publication, Disposal of
radioactive waters into seas, oceans and surface waters." pp. 267-289.
Wallace, A., V. Q. Hale, and C. B. Joven (1969), "DTPA and pH effects on leaf
uptake of 59Fe, 65Zn, 137Cs, 2ttlAm, and 210Pb." J. Amer. Soc, Hort. Sci., 94:
(6), pp. 684-686.
Wallace, A. (1972a), "Effect of soil pH and chelating agent (DTPA) on uptake
by and distribution of 2U1Am in plant parts of bush beans." Radiat. Botany,
12: pp. 433-435.
Wallace, A. (1972b), "Increased uptake of 2ttlAm by plants caused by the
chelating agent DTPA." Health Phys., 22: pp. 559-562.
Williams, J. E. (1967), "Biological transport of 65Zn in a South Carolina
broomsedge field." Proceedings, Second National Symposium on Radioecology.
May 15-17, 1967. Ann Arbor, Michigan. CONF-670503, pp. 665-671.
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
i; REPORT NO.
EPA-600/3-76-005
2.
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
AMERICIUM - ITS BEHAVIOR IN SOIL AND PLANT
SYSTEMS
5. REPORT DATE
January 1976
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
K. W. BROWN
8. PERFORMING ORGANIZATION REPORT NO
I. PERFORMING ORGANIZATION NAME AND ADDRESS
Environmental Monitoring and Support Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
_ Las Vegas. Nevada 89114
12. SPONSORING AGENCY NAME AND ADDRESS
Same as above.
10. PROGRAM ELEMENT NO.
1FA083
11. CONTRACT/GRANT NO.
13. TYPE OF REPORT AND PERIOD COVERED
Final
14. SPONSORING AGENCY CODE
EPA-ORD, Office of Health
and Ecological Effects
15. SUPPLEMENTARY NOTES
16. ABSTRACT
The small amount of data available on the behavior of americium in
plant and soil systems is reviewed and found lacking in several critical
areas. Although some studies have been done on the physical and chemi-
cal interaction of americium on these systems, most of them were short-
term and limited in scope. As americium is classified as a hazardous
radionuclide and is likely to increase in importance as an environmental
pollutant, further study is suggested. Also, the use of americiuro as a
tool for measuring various soil parameters is discussed.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b. IDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group
Absorption
Americium
Agronomy
Isotopes
Plant metabolism
Plutonium
Radioactivity
Biosphere
Radioactive pollutants
Uptake
02D
06C
18B
21. NO. OF PAGES
16
8. DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
19. SECURITY CLASS (ThisReport)
UNCLASSIFIED
20. SECURITY CLASS (Thispage)
UNCLASSIFIED
22. PRICE
EPA Form 2220-1 (9-73)
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